JPS6020195Y2 - disk clamp device - Google Patents

Description

[Detailed description of the invention] This invention relates to an improvement of a disc clamp device that fixes a disc such as a record or a video disc to a turntable. By arranging a permanent magnet and a magnetic material that perform magnetic attraction inside the center hole of the disk with no disk intervening between them, the magnetic attraction is strengthened and the disk is made stronger. The object is to fix the disc on the turntable and to clamp the disc by aligning the center of the disc accurately with the center of the turntable.

Conventionally, there has been a disc clamping device of this type as shown in FIG.

That is, a is a turntable, which is fixed to a rotating shaft.

A cap d into which the center hole of the disk C fits is provided at the tip of the rotating shaft so that it can be slid up and down with a suitable push-up edge provided by a spring e.

Further, the peripheral surface of the cap d has a truncated conical shape with a gentle taper.

f is a claw that contacts the disk C in order to ground the disk C, which is provided in an appropriate number on the circumferential surface of the cap d, and when the disk C is fitted, this claw allows the disk C to pass through the center hole and is turned. When table a rotates, centrifugal force causes cap d to
protrudes from the periphery of the disk C and contacts the disk C.

When the center hole of the disc C is fitted into the cap d and the disc C is placed on the disc, the cap d is lowered by the weight of the disc C against the push-up blade of the spring e until the disc C contacts the turntable a.

When the turntable a is rotated, the medium claw f protrudes from the circumferential surface of the cap d due to centrifugal force, and comes into contact with the periphery of the center hole of the disc C to provide grounding, as shown in the figure. However, the contact push-up blade of this pawl f is small, and it can be said that there is almost no clamping action to press and fix the disc. Also, if the disc C is bent or distorted, , furthermore, the above effect disappears.

Here, grounding the disk means, for example, covering the part of the conductive surface where the geometrical shape changes with a dielectric material, where the information signal is recorded as a geometrical shape change. This means that the conductive surface of the disc is grounded, and during playback, the pickup is scanned over the portion recorded as a change in the geometrical shape covered with a dielectric material. The recorded information signal is reproduced by detecting the change in capacitance between the recorded portion and the recorded portion.

FIG. 5 shows another example of the conventional disk clamp device, in which a thin sheet-like disk C' is placed and fixed on a small turntable a' attached to a rotating shaft b'. A center hole is formed concentrically on the upper surface of the turntable a' or fitted with a ring-shaped protrusion g, and the disk C' is placed on the turntable a', provided on the lower surface of the outer periphery of the pressing plate. The disk C' is clamped by a permanent magnet i that is attracted to the turntable a' by narrowing the periphery of the center hole of the disk C'.

This disk clamping device can adequately clamp sheet-like thin disks, but if the disk is thick < (17F!
171 or more), there is a drawback that the clamping is not sufficient.

In addition, the dimensional accuracy of the center hole of the disk is not so required when the disk is thin because the center hole can become large to some extent, but when the disk is thick, it is required, and in general, the center hole of the disk is There is usually some variation in the size of the disc, and when the center hole of such a disc is fitted into the ring-shaped protrusion g integrally formed on the turntable a', as in this example, teeth,
This may cause looseness or a failure to fit.

This invention provides a disk clamping device that eliminates the above-mentioned conventional drawbacks, and the embodiment shown in FIGS. 1 to 3 will be described in detail.

First, referring to FIGS. 1 and 2 showing the first embodiment, the turntable A will be explained according to its assembly order. 1 is a rotating shaft (center axis of the turntable), and a pulley 2 is attached to the tip of the turntable A. is fixed.

The tip end of this rotary shaft 1 has a smaller diameter.

Reference numeral 3 denotes an elevating member provided in this small-diameter portion and having a fitting protrusion with a tapered circumferential surface that fits into the center hole of the disk. It is formed in the shape of a conical head and is attached so as to be slightly movable in the axial direction, and is further attached to the tip of the rotating shaft 1 through a ferromagnetic washer 4 having an outer diameter larger than the diameter of the rotating shaft 1. A screw 5 having a truncated cone-shaped head 5a is screwed on to prevent the elevating member 3 from coming out.

Further, in this embodiment, an annular ferromagnetic body 6 is attached to the upper surface of the elevating member 3 to be attracted to a permanent magnet provided on the lower surface of the pressing plate, which will be described later.

This ferromagnetic material 6 is necessary when the elevating member 3 is made of plastic acid and non-magnetic material, but is not necessary when the elevating member 3 is made of ferromagnetic material.

In this embodiment, six axial notch grooves 7 are provided on the outer circumferential surface of the elevating member 3 and the outer circumferential surface of the annular ferromagnetic body 6 provided as described above.

Reference numeral 8 denotes a vertically movable plate having a truncated cone shape in appearance, with a flange 8a formed at its bottom, and a flat top 8b on which the periphery of the center hole of the disk 9 is placed. Furthermore, a through hole 8c is formed extending from the top end to the bottom (in the embodiment, the through hole portion is cylindrical).

) Six ribs 10 are formed on the inner wall of the through hole 8c to fit into notched grooves 7 formed in the elevating member 3 and the annular ferromagnetic body 6.

Then, a spring 11 is interposed on the lower surface of this vertical movable plate 8, and the through hole 8c of this vertical movable plate 8 is fitted to the outer periphery of the elevating member 3, and the rib 10 is fitted into the notch groove 7. The vertical movable platen 8 is fitted onto the outer periphery of the elevating member 3 from above.

Thereafter, a through hole 1 having a diameter larger than the outer diameter of the vertical moving plate 8 and smaller than the flange 8a formed at the bottom of the vertical moving plate 8 is formed.
A turntable component 12 having a hole 2a formed in the center thereof is fixed concentrically to the upper surface of the pulley 2 attached as described above with screws or the like.

Therefore, the flange 8a formed at the bottom of the vertical moving platen 8
is assembled so that it is located below the turntable component 12.

Since it is assembled in this manner, when the disc 9 is not placed, the vertical movable platen 8 is pushed up by the spring 11 until its flange 8a abuts against the lower surface 12b of the turntable component 12.

As described above, the assembly of turntable A is completed.

Next, the pressing member B will be explained according to its assembly order. Reference numeral 13 is a component of the pressing member that presses and clamps the disk 9 placed on the turntable component 12, and the center part of the lower surface of the pressing member B is A tapered recess 13a is formed into which the tapered head 5a of the screw 5 screwed onto the upper end of the rotating shaft 1 fits, and a tapered hole 13b is formed at the center of the upper surface of the recess 13a, and a tapered hole 13b is formed at the center of the upper surface of the recess 13a. An annular groove 13c is formed in the portion, and a steel ball 1 is inserted into the tapered hole 13b.
4 is fitted.

Further, a permanent magnet 15 is provided on the lower surface of the component 13 of the pressing member to attract the annular ferromagnetic material 6 provided on the upper surface of the elevating member 3, and this permanent magnet 15 is attached in the upper and lower direction. Although it has a magnetic annular shape, it may be divided into several pieces.

Furthermore, an annular pressing protrusion 13d is protruded from the lower surface of the component 13 of the pressing member.
The peripheral portion of the center hole of the disk 9 placed on the flat portion 8b at the upper end of the disk is pressed.

Reference numeral 16 denotes a cup, and the steel ball 1 is fitted into a tapered hole 13b formed at the center of the upper surface of the component 13 of the pressing member.
Rib 1 whose lower surface abuts the apex of 4 and protrudes from the periphery of the lower surface.
6a is loosely fitted into an annular groove 13 formed on the upper surface of the component 13 of the pressing member (the rib 16a does not contact the annular groove 13c).

This cup 16 has a screw rod 1 protruding from the center of its upper surface.
6b is inserted into the arm 17, and the nut 18 is tightened to be attached to the arm 17.

A guide 19 is provided around the lower surface of the arm 17 so as to hold the outer periphery of the component 13 of the pressing member so as not to normally contact the outer periphery.

This guide 19 is provided to hold the component 13 of the pressing member and pull it up toward the turntable A side when the arm 17 is pulled up.

As described above, the assembly of the pressing member B is completed.

Next, to explain its operation, a disk 9 is placed on the vertical movable platen 8 which is pushed up by the spring 11, and the arm 17 is placed around the center hole of the disk 9.
The arm 17 is pressed by bringing into contact the pressing protrusion 13d of the component 13 of the pressing member held by the guide 19 provided at the.

As a result, the vertical movable platen 8 descends until the disk 9 placed thereon comes into contact with the turntable component 12.

At this time, the tapered recess 13a formed at the center of the lower surface of the pressing member component 13 fits into the tapered head 5a of the screw 5 screwed onto the tip of the rotating shaft 1 with a small gap.

Then, the component 13 of the pressing member is pulled down by the permanent magnet 15 attached thereto being attracted to the ferromagnetic washer 4 provided at the upper end of the rotating shaft 1, and the component 13 of the pressing member is lifted and lowered by fitting into the center hole of the disk 9. The member 3 is attracted by the permanent magnet 15 and pulled up slightly.

Therefore, the component 13 of the pressing member presses the disk 9 downward, and the elevating member 3 is fitted into the center hole of the disk 9 and pulled upward, so that the disk 9
is firmly pressed against the turntable component 12 and fitted into the elevating member 3 without play.

Furthermore, the flatness of the disk 9 and its concentricity with respect to the rotating shaft 1 are maintained accurately.

At this time, the component 13 of the pressing member comes into contact with the cup 16, which is a non-rotating part, only by the steel ball 14, so that it rotates together with the disk 9 without being subjected to rotational resistance.

The vertically movable platen 8 for pushing up the disk 9 to a predetermined height, which has been explained in the above embodiment, is necessary for an automatic disk loading/unloading device (not shown).

Generally, for the purpose of simply holding the disc accurately on the turntable, a configuration as shown in FIG. 3 may be used.

That is, the difference from the above embodiment is that the vertical movement plate 8 is eliminated, and the pressing protrusion 13d formed on the outer periphery of the lower surface of the component 13 of the push-up member directly pushes the disc 9 onto the turntable component 12. This is the point of pressure.

In addition, a pin 20 is provided at the center of the upper surface of the component 13 of the pressing member.
is provided, and this pin 20 is loosely fitted into the arm 17 so as not to come off, and as shown in FIG. Therefore, the component 13 of the pressing member rotates together with the disk 9 while pressing the disc 9, and when removing the component 13 of the pressing member, lift the arm 17, and the component 13 of the pressing member is removed.
3, the component 13 of the pressing member can be removed.

In this embodiment, the elevating member 3 having the fitting protrusion is shaped like a truncated cone, but it goes without saying that they may also be shaped like a polygonal pyramid such as a truncated triangular pyramid or a truncated square pyramid. .

In addition, a ferromagnetic material 6 is placed on the turntable A side, and a pressing member B is placed on the side of the turntable A.
Although the permanent magnets 15 are provided on each side, they may be provided in the opposite direction.

As explained above, this invention consists of a turntable that is attached to the rotating shaft of the turntable and rotates with a disk placed thereon, and a turntable that is placed opposite the upper end of this rotating shaft and rotates around the center hole of the disk. a pressing member that presses against the table side; an elevating member that is movable up and down on the rotating shaft of the turntable; and a lifting member that is attached to the upper end of the rotating shaft of the turntable to prevent the elevating member from being pulled out. a stopper member made of a permanent magnet or a ferromagnetic material; a permanent magnet or a ferromagnetic material attached to the pressing member;
a permanent magnet or a ferromagnetic material attached to the elevating member; the elevating member is provided with a fitting protrusion having a tapered peripheral surface that fits into the center hole of the disk; and the pressing member A permanent magnet or a ferromagnetic material attached to the elevating member is placed facing each other inside the center hole of the disk so that the pressing member and the elevating member are attracted to each other, and the disk is placed on the turntable.

When the pressing member is placed in contact with the disk on the turntable and pressed to a predetermined position, the pressing member is attracted to the rotating shaft by the magnetic attraction action of the permanent magnet. The pressing member and the elevating member are attracted to each other, and the disc is rotated on the turntable with its center hole guided by the circumferential surface of the fitting protrusion and its center position aligned with the rotation center of the turntable. Since we have provided a disc clamping device that is configured to be fixed on the turntable, even if, for example, the size of the center hole of the disc varies when placing and fixing the disc on the turntable, the pressing member can be easily removed. This variation can be easily absorbed by the vertical movement of the pressing member and the lifting member due to the magnetic attraction of the ejecting prevention stopper member and the lifting member, and it is possible to reliably align the center of the disc with the rotation center of the turntable. At the same time, it is possible to prevent play from occurring between the center hole of the disk and the fitting protrusion, so that the needle will not mistrack when playing signals using a ruthless information recording medium such as a video disk. It does not cause such problems and can reproduce faithful signals.

In addition, since a permanent magnet and a ferromagnetic material are arranged between the pressing member and the turntable and inside the center hole of the disk to exert an attractive action, the disk is placed between the permanent magnet and the ferromagnetic material. The disc can be clamped to the turntable with strong force even if the disc is thick.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing the first embodiment of this invention, Fig. 2 is a vertical sectional view of the same assembly, Fig. 3 is a longitudinal sectional view of the second embodiment, and Figs. The figure is a longitudinal sectional view showing a conventional example. A... Turntable, B... Pressing member, 1... Rotating shaft, 3... Fitting protrusion provided near the center of the top surface of the turntable. 4... Stopper member for preventing the lifting member from being pulled out, 6... Ferromagnetic material, 9... Disc, 12...・Turntable component, 13
... Components of the pressing member, 15 ... Permanent magnet.

Claims (1)

[Scope of utility model registration request] a turntable that is attached to a rotating shaft of the turntable and rotates with a disk placed thereon; a pressing member that is disposed opposite to the upper end of the rotating shaft and presses a peripheral portion of the center hole of the disk toward the turntable; an elevating member provided to be movable up and down on the rotating shaft of the turntable; and a stopper member made of a permanent magnet or ferromagnetic material attached to the upper end of the rotating shaft of the turntable to prevent the elevating member from being pulled out. and a permanent magnet or ferromagnetic material attached to the pressing member, and a permanent magnet or ferromagnetic material attached to the elevating member, and the elevating member has a circumference that fits into the center hole of the disk. A fitting protrusion having a tapered surface is provided, and a permanent magnet or a ferromagnetic material attached to the pressing member and the lifting member is placed inside the center hole of the disk so that the pressing member and the lifting member are attracted to each other. When the disks are placed on a turntable and pressed to a predetermined position with the pressing member in contact with the disk on the turntable,
As the pressing member is attracted to the rotating shaft by magnetic attraction by the permanent magnet, the pressing member and the elevating member are attracted to each other, and the center hole of the disk is aligned with the circumferential surface of the fitting protrusion. A disk clamp device configured to be guided and fixed on a turntable with its center position aligned with the rotation center of the turntable.